Next.js 15 Server Components: Full Stack React Without the Complexity
React Server Components in Next.js 15 blur the line between frontend and backend. Components fetch data directly, server actions handle mutations, and the client receives only the HTML it needs.
Server Components by Default
Every component in the App Router is a Server Component unless you add "use client". This means database queries, API calls, and file reads happen at the component level:
// This runs on the server — no API endpoint needed
async function ProductPage({ params }) {
const product = await db.products.findById(params.id);
const reviews = await db.reviews.findByProduct(params.id);
return (
<ReviewList reviews={reviews} />
<AddReviewForm productId={params.id} />
);
}
Server Actions for Mutations
No more API routes for form submissions. Server Actions are functions that run on the server, called directly from client components. TypeScript ensures type safety across the boundary.
Streaming SSR
Wrap slow components in Suspense. The page shell streams immediately, and slow sections fill in as they resolve. Time to First Byte drops to milliseconds even for data-heavy pages.